Drawing compass



April 1967 R. w. SVELLECK 3,

DRAWING COMPASS Filed May 4, 1965 INVENTOR. ROBERT W. SELLECK ATTORNEYS United States Patent 3,313,028 DRAWING CQMPASS Robert W. Seileck, 2952 Senter Road, San Jose, Calif. 55111 Filed May 4, 1965, Ser. No. 453,073 2 Claims. (ill. 33-156) This invention relates to improvements in drawing compasses, dividers and the like.

An object of this invention is to provide an improved drawing compass, divider and the like which may be readily adjusted to draw circles or arcs of different radii or make measurement.

Another object of this invention is to provide an improved drawing compass, divider or the like which is adjustable by means of an improved finger actuated wheel having tooth-like projections that are oriented so as to make it easy to determine the direction of rotation of said wheel for enlarging or reducing adjustments of the compass, divider or the like.

Another object of this invention is to provide an improved device such as a drawing compass, divider or the like that is provided with a mechanism for making delicate adjustments thereof, said device also being provided with prop means for holding it in an inclined position when it is resting on a supporting surface so that the mechanism providing delicate adjustment to the device is held clear of the supporting surface.

Other and further objects of this invention will be apparent to those skilled in the art to which it relates from the following specification, claims and drawing.

Referring to the drawing briefly:

FIG. 1 is a side view of the improved drawing compass showing it in a reclined position on a supporting surface;

FIG. 2 is a view of the compass shown in FIG. 1 looking down thereon;

FIG. 3 is a side view of a modified drawing compass showing it in a reclined position on a supporting surface; and

FIG. 4 is a view showing the drawing compass illustrated in FIG. 3 in erect position.

Referring to the drawing in detail, reference numerals and 11 designate a pair of adjustable arms of a drawing compass. The arm 10 is provided with a member 1 2 such as a pen or pencil held clamped in one end thereof while the arm 11 is provided with a pointed member 13 which is held clamped in the corresponding end thereof. The other ends of the arms 10 and 11 are held against the pivoting or bearing member 140 by the curved spring 16, the ends 16a and 16b of which engage the arms 10 and 11, respectively. Thus, the spring member 16 applies pressure against the arms 10 and 11 adjacent the bearing 14a urging the working ends of the arms carrying the members 12 and 13 apart. The conventional finger grip 17, which is provided with a knurled surface, is attached to the spring 16 and the hearing or pivot member 14a by the rod 17a.

Each of the arms 10 and 11 is made of a pair of spaced members, as shown in the case of arm 1.1 in FIG. 1. Threaded members 19 and 21 are provided to the mid portions of the arms 10 and 11, respectively, and these members are held between the spaced arm members in suitable apertures provided to -these members. The members 19 and 21 are provided with threaded holes therethrough for receiving the threaded parts 18 and of the compass adjusting member which is provided with a finger actuated wheel 22 attached to the middle part thereof. The threads on the parts 18 and 20 of this threaded rod are of different hands; that is, one part is provided with a right hand thread, whereas, the

other part is provided with a left hand thread. Thus, by rotating the finger Wheel 22 which is attached to this compass adjusting member, the arms 10 and 11 are moved either toward each other or further apart, as desired by the draftsman using the compass.

The finger wheel 22 is provided with a series of toothlike projections 23 around the circumference thereof, and these tooth-like projections are all pointed either clockwise or counterclockwise so that they provide relatively fine edges with gaps therebetween which the draftsman may engage with a thumb and forefinger to provide small and accurate adjustments to the spacing of the arms 10 and 11 by rotation of the threaded members 1840. By shaping the projections as illustrated, the draftsman using the device can determine from the touch or feel of the wheel 22 the rotation thereof for reducing or enlarging the radius of the compass. For enlarging the radius of the compass the wheel 22 shown is rotated by pressing against the abrupt sides of the teeth engaged by the thumb and forefinger. This compass is also provided with props 14 and 15 which are attached to the outer ends of the bearing or pivot member 14a. These props are of suificient length so that when the compass is in a reclined position on a supporting surface, as shown in FIG. 1, the finger wheel 22 is supported clear of such surfaces. Thus, the adjustment of the compass cannot be disturbed by having the finger wheel 22 engage the supporting surface when the compass is placed in reclining position.

A modified form of this drawing compass is shown in FIGS. 3 and 4. This compass is provided with arms 10a and 11a which are provided with a pen or pencil 12a and a sharp point 13a, respectively, at their working ends. The other ends of the arms are pressed against the bearing or pivot member 15b by the spring 16m. The ends and 16d of the spring engage the arms 10a and 11a adjacent the bearing 15b, as shown, and press these end portions against the bearing member 15b, and at the same time it urges the working ends of the arms apart. The compass is also provided with a threaded rod for adjustment thereof having sections 18a and 22a threaded in opposite hands. A finger wheel 22a is attached to the central part of this threaded rod for rotation thereof and threaded members 19a and 21a are positioned in the mid portions of arms 10a and 11a, respectively, for receiving the threaded portions of the rods 18a and 22a, respectively.

Pointed tooth-like projections 23a, which are similar to the projections 23 of the compass shown in FIG. 1 but smaller, are provided to the finger wheel 22a. These projections 23a may be arranged on sections of the periphery of finger wheel 22a. These projections are provided to this finger wheel so that the draftsman may feel these projections and the spaces therebetween with his thumb and forefinger and determine the direction of rotation of the wheel to produce the desired larger or smaller radius of the compass. At the same time, minute rotation of the member 22a may be obtained without excessive pressure being exerted thereon. Suitable props 14a and 15a are provided to the opposite ends of the bearing or pivot member 15b and these props are of sufiicient length so that when the compass is placed on the supporting surface in reclined position, the finger wheel 22a is supported clear of the surface. The compass is also provided with a conventional finger grip 17a for the purpose of manipulating the compass during use thereof.

While I have shown a preferred embodiment of the invention, it will be understood that the invention is capable of variation and modification so that its scope should be limited only by the scope of the claims appended hereto.

finger engaging member is substantially circular and the 7 surface thereof is provided with tooth-like projections directionally related to the direction of rotation of said finger engaging member shaped to facilitate determining the direction of rotation of'said finger engaging member from the feel ,of said projections to the touch, the threads on said threaded rod and said threaded members being such that rotation of said rod in one direction spreads said other end parts of said arms, and rotating it in the other direction brings said other end parts together, said pivoting means having an axis about which said arms are adapted to be rotated, and prop means attached to the opposite sides of said pivoting means extending away from said pivoting means substantially in the direction of said axis thereof, said prop means holding the pivoted end parts of said arms for holding these end parts of said arms in elevated position when the compass is reclined on a supporting surface, said prop means being long enough so that it supports said finger engaging member away from said supporting surface.

2. In a drafting device such as a drawing compass, divider or the like, the combination comprising a pair of arms, means pivotally attaching one of the end parts of each of said arms together so that the other end parts of said arms may be moved toward or away from each other, a threaded rod extending between the mid portions of said arms, threaded members attached to said mid portions of said arms engaging the threads of said rod, a finger engaging member attached to said rod for rotating said rod, the threads on said threaded rod and said threaded members being such that rotation of said rod in one direction spreads said other end parts of said arms, and rotating it in the other direction brings said other end parts together, said finger engaging member being substantially circular and the surface thereof being provided with tooth-like projections directionally related to the direction of rotation of said finger engaging member to facilitate determining the direction of said finger engaging member from the feel of said projections to the touch.

References Cited by the Examiner- UNITED STATES PATENTS 2,298,000 10/1942 Eubanks 33-154 2,375,557 5/1945 Hurley 33167 2,878,571 3/1959 Johnson 33--l66 LEONARD FORMAN, Primary Examiner.

WM. D. MARTIN, Assistant Examiner. 

1. IN A DRAFTING DEVICE SUCH AS A DRAWING COMPASS, DIVIDER OR THE LIKE, THE COMBINATION COMPRISING A PAIR OF ARMS, THREADED MEMBERS ATTACHED TO SAID MID PORTIONS OF EACH OF SAID ARMS TOGETHER SO THAT THE OTHER END PARTS OF SAID ARMS MAY BE MOVED TOWARD OR AWAY FROM EACH OTHER, A THREADED ROD EXTENDING BETWEEN THE MID PORTIONS OF SAID ARMS, THREADED MEMBERS ATTACHED TO SAID MID PORTIONS OF SAID ARMS ENGAGING THE THREADS OF SAID ROD, A FINGER ENGAGING MEMBER ATTACHED TO SAID ROD FOR ROTATING SAID ROD, SAID FINGER ENGAGING MEMBER IS SUBSTANTIALLY CIRCULAR AND THE SURFACE THEREOF IS PROVIDED WITH TOOTH-LIKE PROJECTIONS DIRECTIONALLY RELATED TO THE DIRECTION OF ROTATION OF SAID FINGER ENGAGING MEMBER SHAPED TO FACILITATE DETERMINING THE DIRECTION OF ROTATION OF SAID FINGER ENGAGING MEMBER FROM THE FEEL OF SAID PROJECTIONS TO THE TOUCH, THE THREADS ON SAID THREADED ROD AND SAID THREADED MEMBERS BEING SUCH THAT ROTATION OF SAID ARMS, AND ROTATING IT IN THE SAID OTHER END PARTS OF SAID ARMS, AND ROTATING IT IN THE OTHER DIRECTION BRINGS SAID OTHER END PARTS TOGETHER, SAID PIVOTING MEANS HAVING AN AXIS ABOUT WHICH SAID ARMS ARE ADAPTED TO BE ROTATED, AND PROP MEANS ATTACHED TO THE OPPOSITE SIDES OF SAID PIVOTING MEANS EXTENDING AWAY FROM SAID PIVOTING MEANS SUBSTANTIALLY IN THE DIRECTION OF SAID AXIS THEREOF, SAID PROP MEANS HOLDING THE PIVOTED END PARTS OF SAID ARMS FOR HOLDING THESE END PARTS OF SAID ARMS IN ELEVATED POSITION WHEN THE COMPASS IS RECLINED ON A SUPPORTING SURFACE, SAID PROP MEANS BEING LONG ENOUGH SO THAT IT SUPPORTS SAID FINGER ENGAGING MEMBER AWAY FROM SAID SUPPORTING SURFACE. 